Читать книгу English Industries of the Middle Ages - L. F. Salzman - Страница 8

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Tin mining claims an antiquity unsurpassed by any other industry in this country, but with what degree of justice may well be doubted. The claim of the western promontory of Britain, later known as Cornwall and Devon, to be the Cassiterides or Tin Islands whence the Phœnicians obtained their stores of that metal at least five hundred years before the Christian era rests upon rather shadowy grounds.[204] Diodorus Siculus, who wrote about B.C. 30, is the first writer definitely to connect Britain with the tin trade, and his statements appear to be based rather upon a doubtful understanding of earlier topographers than upon actual knowledge. According to him the tin was produced in the promontory of 'Bolerium' and brought to the island of 'Ictis,' whence it was transported to Gaul. If 'Bolerium' is Cornwall, then there is no reason to doubt that 'Ictis' is 'Insula Vectis,' or the Isle of Wight, which was at that date still connected to the mainland by a narrow ridge of rock, covered at highwater, but dry at low water, as 'Ictis' is said to have been.[205] It is certainly strange, if an ancient and well-established trade in tin really existed in Britain when the Romans came over, that that race, with its keen eye for metallic wealth, should have made no use of the tin mines of Cornwall. Yet there is no reference to these mines in the literature of the period of the Roman occupation, nor are there traces of anything approaching an occupation of Cornwall by the Romans, who appear to have ignored this corner of Britain completely. After the departure of the Romans, and before the Saxons conquered this district, which did not happen till the middle of the tenth century, there is some evidence of tin being worked here, as Cornish tin is said to have been carried over to France in the seventh century, and in a life of St. John of Alexandria, who died in 616, there is a story of an Alexandrian galley coming to Britain for tin.[206] That the Saxons worked the tin seems probable from the discovery of Saxon remains in the St. Austell tin grounds and elsewhere,[207] but the industry can hardly have been of any great importance at the time of the Norman Conquest, as there is no reference to it in the Domesday Survey.

While the history of tin mining in Britain prior to the middle of the twelfth century is problematical, there is from that time onwards an immense mass of material bearing upon the subject. This material has been patiently examined by Mr. George Randall Lewis, and summarised in his work on The Stannaries,[208] a book so full and complete that I have saved myself much labour by basing this chapter almost entirely upon it.

There are, as might be expected, many analogies between the mining of tin and the mining of lead. The processes were very similar, and the laws governing the workers had much in common, but it is in the case of the Stannaries that we find the full development of the 'free miner,' so far as England is concerned. Certain initial differences in the methods employed are observable owing to the form in which tin is obtained. Tin, like other metals, exists in veins or lodes embedded in the rock at various depths; where these veins outcrop on the banks of a stream they are broken up by the action of the water and climatic variations, the resultant pile of stanniferous boulders being known as 'shode'; the waters of the stream constantly wear away small pieces of the tin ore and carry it downwards until, owing to its heavy specific gravity, the tin sinks, forming a deposit in the bed of the stream which may sometimes be as much as twenty feet thick. It was this third class of alluvial tin which was alone worked in prehistoric and early medieval days. This might safely be assumed, but rather remarkable confirmation is obtained from an account of tin worked for Edmund of Cornwall in 1297. From this it appears that twenty-eight and a half 'foot-fates' of ore produced a thousand-weight (1200 lbs.) of 'white tin,' the proportion corresponding pretty closely with those—three 'foot-fates' of ore to yield 105 lbs. of metal—given in the sixteenth century by Thomas Beare for alluvial or 'stream' tin, which was far richer than mine tin.[209] It cannot have been very long before the miners realised that the stream tin was carried down by the water, and started to search for its source. The 'shode,' or boulder tin, must therefore have been worked almost as early as the alluvial deposits, and the final stage was the working of the 'lode.' In this lode mining the first workings were no doubt shallow trenches and confined to places where the ore lay close to the surface; a somewhat greater depth was obtained by 'shamelling,' the trench being carried down in stages, a 'shamell' or platform being left at each stage at the height to which the miner could throw his ore; finally came the deep shaft with galleries. But here, as in all mining, the question of drainage came in. Where the workings were quite shallow the water could be baled out with wooden bowls, or a 'level,' or deep ditch, could be dug. For greater depths the adit, or drainage gallery (see above, p. 50), was available, and although Mr. Lewis[210] cannot find any instance of the use of the adit in tin mining before the seventeenth century, it does not seem reasonable to doubt that it was in use much earlier. Exactly when pumps and other draining machines were introduced into the tin mines is not clear, but probably they were little used during our medieval period, when few of the mines were of any great depth.[211]

The primitive miner, when he had got his ore with the aid of his simple tools, a wooden shovel and a pick, also in earliest times of wood, but later of iron, constructed a rough hearth of stones on which he kindled a fire. When it was burning strongly he cast in his ore and afterwards collected the molten tin from the ashes. The next stage was to construct a regular furnace, exactly similar in type to the boles or furnaces used for lead-melting (see above, p. 51). These furnaces were enclosed in a building, the 'blowing-house,' in early times a rough thatched shanty, which was burnt from time to time to obtain the metallic dust which had lodged in the thatch, but afterwards more substantial. The cost of a 'melting howse' (80 feet by 20 feet) built at Larian in Cornwall by Burcord Crangs, a German, in the time of Queen Mary, was about £300, composed as follows:[212]—